Pesticides in Food and Home May Increase ADHD Risk in Children

With reports of attention deficit hyperactivity disorder (ADHD) seemingly on the rise, researchers in a recent study analyzed the theory that household pesticides and those present in food may account for a great majority of new ADHD cases in the United States.

Statistics from a nationally representative sample of American children aged 8-15 who were tested for ADHD and had urine samples that tested for common pesticides were analyzed in this study led by Marc C. Weisskopf, PhD, ScD, of the Harvard School of Public Health.  The pesticides in question were organophosphate pesticides like malathion, which is used to kill insects on agricultural crops.

The study results indicate that children with higher-than-average levels of pesticide metabolites in their systems were twice as likely to test positive for ADHD as kids with levels that were not detectable.  These findings suggest that pesticides are likely contributing to the growing number of ADHD cases reported in the United States each year.

Unfortunately, it is difficult to pinpoint which children are at highest risk for developing ADHD that is linked to pesticides because it seems that lifestyle is not an indicator of risk.  In fact, many of the foods that contain high levels of organophosphate pesticides are actually foods that are considered healthy for growing children.  The metabolites detected in the study suggest that the children were actually exposed to low levels of the pesticides for a long period of time, yet the levels were enough to affect their development.

While this study does not conclusively prove that organophosphate pesticides cause ADHD in children, its results are congruous with the findings of a 2006 study by Virginia A. Rauh, ScD, MSW, of Columbia University.  Rauh and colleagues determined that children with high exposure to household organophosphate pesticides displayed notable mental and motor skill development delays.

Rauh’s team concluded that most exposure comes from pesticide use on the food children eat, and the effects increase over time.  In fact, children can even be exposed to such pesticides while in the womb, and these children were likely than others to display signs of ADHD.

Both studies that investigated the link between organophosphate pesticides concluded that such chemicals are almost unavoidable because of their presence on the food children eat, however Rauh and her colleagues write, “We need the EPA [Environmental Protection Agency] to take a good look at all these studies and see if the risk warrants dropping the safety limit for these chemicals and tightening their regulation.”